Marrucciite is an extremely rare sulfosalt mineral primarily known from the Jas Roux locality in France. It typically occurs as small metallic, lead-gray grains associated with other sulfide and sulfosalt minerals in hydrothermal deposits.
Is this marrucciite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch marrucciite with a known reference. Marrucciite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark gray with a very weak reddish tint.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular.
Often confused with
Marrucciite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Marrucciite leaves dark gray with a very weak reddish tint, Galena leaves lead-gray.
How to tell apart: Streak differs, so Marrucciite leaves dark gray with a very weak reddish tint, Cinnabar leaves scarlet; luster reads metallic on Marrucciite and adamantine, inclining to metallic when dark; dull in friable material on Cinnabar.
How to tell apart: Streak differs, so Marrucciite leaves dark gray with a very weak reddish tint, Stibnite leaves lead-gray.
Often found alongside marrucciite
Minerals reported to co-occur with marrucciite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₃Pb₁₆Sb₁₈S₄₆
- Mohs hardness
- ~2
- Density
- 6.00 g/cm³
- Colors
- Streak
- Dark gray with a very weak reddish tint
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular
- Cleavage
- Perfect || [010] on (20 1 - )
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a hydrothermal assemblage, within small calcite veinlets crosscutting dolomitic lenses interstratified in a Ba-Fe deposit (Buca Della Vena)
Where rockhounds find marrucciite
Classic worldwide localities
- Buca della Vena mine, near Pietrasanta, Apuan Alps, Italy (type locality)
- Zenderling, near Gelnica, Spišsko-Gemerské Rudohorie Mts., Slovak Republic
Field-hunting tip
Where it forms: In a hydrothermal assemblage, within small calcite veinlets crosscutting dolomitic lenses interstratified in a Ba-Fe deposit (Buca Della Vena). If you start seeing zinkenite, scainiite, chalcostibite in float, you are in the right ground. Typical habit: acicular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify marrucciite?+
Where is marrucciite found?+
Is marrucciite safe to handle?+
What rocks look like marrucciite?+
What minerals are found with marrucciite?+
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Find marrucciite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
